Neopan 1600 is about the only 35mm film I use any more. It has the finest grain of any of the 3 fast films. However, it is only about 800 speed. It doesn't push well. It has a very short toe so the shadows drop to black very quickly. Something I personally like, but doesn't help if you want more speed. I use it as a general purpose film because I love the look, but only shoot it at 800. I wish it came in 120.
If you really want more speed, either Tmax 3200 or Delta 3200 have a bit more real speed and push much, much better. I generally prefer Tmax 3200, it seems to work well in most developers. I could never get a handle on Delta 3200, but kept trying because it is the only one of these available in 120. I found the grain very intrusive and the highlights very flat in anything I used to develop it until I tried Tmax (or Tmax RS) developer. I find this developer ideal for Delta 3200 since it kicks up the contrast in the highlights and gives a little more speed and a little less grain. I actually now prefer Delta 3200 to Tmax 3200, but only in Tmax developer (Tmax developer works pretty well for Tmax 3200 and Neopan 1600 as well).
John